public async Task <Tuple <bool, UserEventDto> > AddDelayAsync(string userId, int eventId, int minutesOfDelay)
        {
            var result = await _userEventRepository.AddDelayAsync(userId, eventId, minutesOfDelay);

            if (result.Status == RepositoryStatus.Ok)
            {
                var userEventDto = _mapper.Map <UserEvent, UserEventDto>(result.Entity.Item2);
                return(new Tuple <bool, UserEventDto>(result.Entity.Item1, userEventDto));
            }
            throw new ServiceException(ErrorCodes.EntityNotFound);
        }